This invention is directed to a novel and improved interface unit which is operable to handle the exchange of signals between an associated communication processor and a communication channel.
The communication channel interface unit of invention is useful in a distributed processing system consisting of a number of processor stations. A user at one station can access data and or run programs resident at another processor station. That the data and or programs are resident at another processor station is for all practical purposes invisible or transparent to the user. In such a system each processor station includes a communication controller which serves the purpose of controlling the exchange of messages between its associated processor and the other processing stations. The communications controller itself includes a communication processor for handling message exchanges. The communication channel interface unit of this invention provide a signal interface between its associated communication processor and the communication channel. In particular, the communication channel interface unit of this invention can be employed in the communication controller described in a copending application, Ser. No. 478,604, filed 3/24/83, in the names of Gerhard Ringel and Gabor Fencsik and entitled "Communication Controller with Slot Reservation".
Interface units which provide signal translation between a communication channel and a communications processor generally comprise one mechanism for message signal transceiver operations and a separate and independent mechanism for channel contention operations.